Rheostat for telephonic instruments



H. KOCH. RHEOSTAT FOR TELEPHONIC INSTRUMENTS. APPLICATION FILED OCT. 20, 1919.

1,356,634. Patented Oc t. 26,1920.

F W] TNESS: g I INVENTOR.

A TTORNEYJ:

V UNITED STATES PATENT OFFICE.

HENRY KOCH, OF JAMAICA, NEW YORK, ASSIGNOR TO DICTOGRAPH PRODUCTS CORPO- RATION, A CORPORATION OF VIRGINIA.

RHEOSTAT FOR TELEPHONIC INSTRUMENTS.

Application filed. October 20, 1919.

To all whom it may concern:

Be it known that I, HENRY KooH, a citizen of the United States, residing at Jamaica, in the county of Queens and State of New York, have invented certain new and useful Improvements in Rheostats for Telephonic Instruments, of which the following is a full, clear, and exact description.

This invention relates to telephonic instruments and has special reference to instruments adapted for the use of persons with impaired hearing, a set of such in struments ordinarily comprising a oortable transmitter, receiver and battery. n connection with such instruments there is sometimes used a rheostat for controlling the in tensity of the 'sound and this rheostat comprises a sectional resistance, a series of contacts and a movable contact arm mounted within or upon the casing of the instrument and independent of the elements of the. instrument itself, so that difficulty has been experienced in finding space for the rheostat and the many connections therefrom to the elements of the instrument itself, which in many cases have to be soldered, thus rendering the device expensive to manufacture The object of the present invention is to combine the rheostat with the instrument in such a manner that the ordinary casing will readily accommodate both device's and the cost will be considerably reduced. I accomplish this result in a transmitting instrument primarily, by mounting the button electrode of the transmitter to rotate in or upon the casing, a suitable handle or gripping device being exposed on the outside of the casing to enable the button to be manipulated and I mechanically and electrically connect with the button the movable arm of the rheostat which then becomes a unit therewith and avoids the necessity of other mechanical connections between these two parts. The resistance coil or coils of the rheostat are then disposed conveniently within the casing to one side of the button, where they will cooperate with the arm.

The invention will now be described in detail with reference to the accompanying drawing in which:

Figure 1 is front view of my improved transmitter with battery attached thereto.

Fig. ,2 is a cross sectional view taken through the center of the transmitter.

Specification of Letters Patent.

Patented Oct. 26, 1920;

Serial No. 331,957.

Fig. 4: is a front View of the transmitter with the cover removed, and

Fig. 5 is a diagrammatic View of the electrical connection.

The transmitter comprises a casing 1, having a removable cover 2, the cover holding a diaphragm 3 of electrical conducting material against a contact ring 4; which is carried on a shoulder 5 of thecasing. The cover has openings 6 to enable the passage of sound to the diaphragm. Rotatably mounted in an opening 7 in the rear wall of the casing is an operating disk member 8, having ribs 9 on its outer face to provide a handle by means of which the disk member is rotated to vary the effective resistance of the rheostat. An electrode 10 of carbon or other suitable electrical conducting material, has a plurality of depressions 11 in one face thereof, each depression containing a plurality of small carbon granules which are held within the depressions by the diaphragm. The casing 1 and disk member 8 have cooperating shoulders to limit the inward movement of the disk member. The electrode and disk member are held in position in the casing by a bolt or screw 13, the head 14 of which is countersunk in the electrode and disk member. A nut 15 on said bolt is disposed within a recess 16 in the rear face of the disk member and compresses a spring 17, which is also within the recess, against the disk member, whereby the disk member and electrode are yieldingly held together in the casing and frictionally against rotation from any adjusted position. The rear face of the casing has graduations 18 thereon which cooperate with an arrow or other indicating mark 19 on the disk member for indicating the condition of the rheostat. The nut 15 has small recesses 20 therein for the reception of a spanner wrench for its operation.

A contact member 21 is carried on the bolt 13 between the electrode and the disk member, and bent up fingers 22 thereof engage in recesses 23 in the disk member so that turning of thedisk member will turn the contact member accordingly. The contact member is provided with an arm 24 which forms the movable part of the rheostat. The resistance of the rheo'stat is preferably a coil 25 of resistance wire, wound in helical grooves on an arcuate rod 26 of some 1nsulatmg material such as hard rubber for example.

The battery 18 is detachably connected to the transmitter by means of split sleeve terminals 27 and 28 which fit over posts 29- and 30 carried by the battery. The terminal 27 is connected to one end of the resistance coil by means of conducting strip 31. The receiver R is connected tothe transmitter by means of wires leading to the split sleeve terminals 32 and 33. The receiver terminal 32 is directly connected to the other battery terminal 28- by conducting .strip 34. The other receiver terminal 33 is connected by strip 35 to the contact ring 4/ Current passes from the battery B to post 30, terminal 28 strip 34, terminal 32, thence to receiver and returning to terminal 33, through strip 35 to contact ring 4, through the diaphragm 3 to the carbon granules 12 1 and electrode 10, thence through contact member 21, arm 24, coil 25, strip 31, terminal 27 and post 29 back to the battery. Any suittble supporting clasp such as 36 may be use Turning of disk member 8 changes the position of arm 24 on the resistance member which varies the resistance in the circuit proportionally to the distance of the .arm

from that end of the resistance member.

which is connected to strip 31. When a new battery is supplied the indicator 19. can be set at the soft position wherein all the resistance is cutin. As the battery deteriorates the disk member can be turned gradually-toward the loud position, thus gradually decreasing the amount of resistance in the circuit.

I claim: i

1. A telephonic instrument comprising an electrode and a rheostat, said electrode be-v ing movable with the movable part ofthe rheostat.

2. A telephonic instrument comprising an elect! ode and a rheostat, said electrode be ing movable with the movable part of the rheostat, the movable part of the rheostat being mounted concentrically with the electrode and electrically "connected thereto.

3. A telephonic instrument comprising a casing, anelectrode mounted to rotate in the.

casing, and a rheostat carried by the casing and having a contact arm carried by the electrode.

4. In a telephonic instrument, a casing, a

transmitter electrode mounted for rotation in the casing, a rheostat in said casing and having two relatively movable parts, one of said parts being mounted for rotation with said transmitter electrode, a diaphragm mounted in position to co-actwith the transmitter electrode, and electrical connectionsing, a rheostat in said casing and havin -ter electrode for making variable contact leading to the other part of the rheostat and I to the diaphragm.

- 5. In a telephonic instrument, the combination of a casing, a transmitter electrode mounted for rotation in the casing, a rheo-- stat in said casing having a movable contact member mounted for rotation'with the transmitter electrode, a diaphragm mounted in position to co-act with the transmitter electrode and electrical connections leading to the rheostat and to the diaphragm.

6. A telephonic instrument comprising a casing, a transmitter electrode in said casa. moving contact arm mounted for rotation on an axis concentric with the axis of the transmitter electrode, adiaphragm co-acting with said transmitter electrode, and electristat, contact arm, transmitter electrode and diaphragm.

7. A telephonic instrument comprising a casing, a transmitter electrode mounted for rotatlon in saidcasing, a contact arm carried thereby, a resistance member arranged substantially concentric with the axis of rotation of the electrode and in position to be engaged by said contact arm, and electrical connections including in series the resistance member, the contact arm and the transmitter electrode.

8. A telephonic instrument comprising a casing, a transmitter electrode within the casing, a resistance member within the casing, contact means carried by the transmitwith said resistance member, and electrical connections including in series the resistance member, the contact means, and the transmitter electrode.

9. A telephonic instrument comprising a casing, a transmitter electrode within the casing, a resistance member within the casing, contact means connected to the transmitter electrode for making variable contact with said resistance member, electrical connections -including in series the resistance member, the contact means, and the transmitter electrode, and operating means accessible from 'the exterior of the casing for varying the position of the contact means with respect to the resistance member to vary the amount of resistance in the circuit. 1

10. In a telephonic instrument, a casing, a transmitter electrode mounted for rotation in the casing, a rheostat in said casing and having two relatively movable parts, one of said parts being mounted for rotation with said transmitter electrode, a diaphragm mounted in position to co-act with the transmitter electrode, "electrical connections including in series the rheostat, transmitter electrode and. diaphragm, and operating means accessible from the exterior of the casing for rotating the transmitter electrode to vary the relative position of the rheostat parts to thereby regulate its effective resistance.

11. In a telephonic instrument, the combination of a casing, a transmitter electrode mounted for rotation in the casing, a rheostat in said casing having a movable contact member mounted for rotation with the transmitter electrode, a diaphragm mounted in position to co-act with the transmitter electrode and electrical connections including in series the rheostat, contact member, transmitter electrode and diaphragm, and operating means accessible from the exterior of the casing for rotating the transmitter electrode and contact member to vary the effective resistance of the rheostat.

12. A telephonic instrument comprising a casing, a transmitter electrode in said casing, a rheostat in said casing and hav'ng a moving contact arm mounted for rotat on on an axis concentric with the axis of the transmitter electrode, a diaphragm co-act;

ing with said transmitter electrode, elec-- trical connections including in series the and diaphragm, and operating means accessible from the exterior of the casing for rotating the contact arm to vary the effective resistance of the rheostat.

13. 'A telephonic instrument "comprising a casing, a transmitter electrode mounted for rotation in said casing, a contact arm'frqarried thereby, a resistance member arranged substantially concentric with the axis of rotation of the electrode and in position to be engaged by said contact arm, electrical connections including in series the resistance member, the contact arm and the transmitter electrode, and operating means accessible from the exterior of the casing for rotating the electrode and contact arm to vary the affective resistance of the resistance mem- 14. A telephonic instrument comprising a casing, a disk member rotatably mounted in one wall of the casing and accessible for manual operation from the exterior of the casing, a contact arm and a transmitter electrode carried by said disk member for rotation therewith, a resistance member within the casing, concentric with the disk member and in position to be engaged by said contact arm as it rotates, and electrical connections including in series the resistance member, the contact arm and the transmitter electrode.

15. A telephonic instrument comprising a casing, a disk member rotatably mounted in one wall of the casing and accessible for manual operation from the exterior of the casing, a contact arm and a transmitter electrode carried by said disk member for rotation therewith, holding means cooperating with said disk member for yieldingly retaining it in any adjusted position, a resistance member within the casing, concentric with the disk member and in position to be engaged by said "contact arm as it rotates, and electrical connections including in series the resistance member, the contact arm and the transmitter electrode.

16. telephonic instrument comprising a casing, a disk member rotatably mounted in one Wall of the casing and accessible for manual operation from the exterior of the I casing, a contact member and a transmitter rheostat, contact arm, transmitter electrode electrode, a bolt passing through the electrode, contact member and disk member for holding them for rotation together and from separation from the wall of the casing, and resilient means arranged for yieldingly holding the electrode, contact member anddisk member against loose play and against rotation from any adjusted position.

17. A telephonic instrument comprising a casing, a disk member rotatably mounted in one wall of the casing and accessible for manual operation from the exterior of the casing, a contact member and a transmitter electrode, a bolt passing through the electrode, contact member and disk member for holding them for rotation together and from separation from the wall of the casing, and a coil spring carried by the bolt for yieldingly holding the electrode, contact member and disk member against loose play and against rotation from any adjusted position.

In witness whereof I subscribe my signature.

HENRY KOCH. 

